Vaned rotary pumps and motors



March 14, 1961 FRASER 2,974,603

VANED ROTARY PUMPS AND MOTORS Filec. June 25, 1958 3 Sheets-Sheet 1 Fig.1.

March 14, 1961 A. FRASER 2,974,603

VANED ROTARY PUMPS AND MOTORS Filed June 25, 1958 3 Sheets-Sheet 2 March 14, 1961 A. FRASER 2,974,503

VANED ROTARY PUMPS AND MOTORS Filed June 25, 1958 3 Sheets-Sheet 3 United States Patent C VANED ROTARY PUMPS AND MOTORS Andrew Fraser,'27 The Vale, London W..3, England Filed June 25, 1958, Ser. No. 744,567 Claims priority, application Great Britain June 28, '1957 Claims. (Cl. 103-121)v The present invention relates to vaned rotary pumps and motors, that is to pumps and motors comprising a stator, a rotor co-operating with the stator to form a plurality of liquid chambers, and one or more vanes arranged to sweep the chambers and displace liquid therefrom upon rotation of the rotor.

Such pumps and motors present the problem of providing a vane of simple construction which will give adequate sealing between the vane surfaces and the sur-' faces that are engaged by the said vane surfaces and are moving relative thereto, and which will maintain such adequate sealing despite wear of the surfaces in sliding engagement. This problem exists but is not acute in pumps or motors operating with low working pressures,

. and becomes acute in pumps or motors operating with high working pressure, e.g. 500 p.s.i. and greater.

The object of the invention is to provide a vaned pump or motor having an improved vane which provides such adequate sealing despite wear in the vane or the surfaces in sliding engagement with the vane.

According to the invention there is provided a rotary pump or motor comprising a hollow stator member and a rotor member rotatably mounted with small clearance between internal opposing side surfaces of the stator,

the rotor and the stator having opposing Peripheral surfaces one of which is circular and the other of which has a non-circular curvilinear profile in a plane perpendicular to the rotational axis of the rotor, the said peripheral surfaces co-operating with the internal side surfaces of the stator to form an annular series of liquid chambers, at least one vane slidably mounted in the member having the circular peripheral surface and arranged to engage the non-circular peripheral surface and thereby sweep said chambers and displace liquid therefrom 'upon rotation of the rotor, and a high pressure liquid conduit and a low pressure liquid conduit communicating'with said chambers on opposite sides of each vane, wherein each vane comprises at least two Vane parts yieldably urged in opposite directions during operation of the pump or motor to provide sealing contact between each vane part and at least one of the said surfaces. The

'two vane parts are yieldably urged in opposite directions by a layer or layers of resilient material bonded to the vane parts and stressed in shear when the vane is mounted ,in position in the pump or motor and this action may be assisted by hydraulic pressure acting on opposing surfaces on the vane parts. r

The invention will now be described with reference to the accompanying drawing, in which:

Figure 1 is a part sectional elevation view of a pump according to the invention,

Figure 2 is a cross sectional view of the pump of ,Figurel taken on the line II-II of Figure 1,

.0f Figure? in an unstressed condition,

Figure 5 is an elevation view of the vane of Figure 4,

' Patented Mar. 14, 1961 r 1 Ce- Figures 6 and 7 are plan and elevation views respective- 1y of another construction of vane suitable for use in the pump of Figure 1,

Figures 8 and 9 are plan and elevation views respectively of yet another construction of vane suitable for use in the pump of Figure 1,

Figure 10 is a cross sectional view of a single vane pump according to the invention,

Figure 11 is a detail view showing the single vane o the pump of Figure 10 mounted in position in the rotor, and V Figure 12 is a perspective view on a larger scale of the single vane of the pump of Figure 10.

The pump of Figures 1 and 2 comprises a stator ring 10 mounted between two annular stator walls 11, 12 which are clamped between two end caps 13, 14 by an annular series of bolts 15 extending through the stator walls 11, 12 and the stator ring 10. A pump shaft 16 is supported in bearings 17, 18 mounted in the central apertures of the annular stator walls 11, 12 respectively, and a rotor 19 is mounted on the portion 20 of the shaft extending between the stator walls 11, 12. One end of i the shaft extends outwards through an aperture in the end cap13 and is drivably connected to a motor (not shown), and the other end of the shaft is in the form of a tube 21 which opens into a liquid inlet port 22 in the end cap 14-. As shown in Figure 2, the portion 20 of the shaft is elliptical in form and is a close fit within a corresponding orifice 23 in the centre of the rotor 19, sufficient clearance being provided between the rotor and the shaft to permit easy sliding movement of the rotor on the shaft.

The stator ring 10 and the spaced apart stator walls 11, 12 form an annular pump chamber for the reception of the rotor 19, the inner peripheral portion of the stator ring 10 and the two opposing side portions of the stator walls 11, 12 being made of self lubricating material, such as, for example, polytetrafluoretaylene, to forrn'a lining for the pump chamber. The peripheral surface of the rotor 19 is cylindrical in form and the opposing wall of the stator ring 10 comprises six part-cylindrical surfaces 24 having a curvature greater than that of the peripheral surface of the rotor and spaced apart by six part-cylindrical surfaces 25 having a curvature approximately equal to that of the peripheral surface of the rotor. The sides of the rotor are a close running fitwith the stator walls 11, 12 and the peripheral surface of the rotor is a close running fit with the part-cylindrical surfaces 25 of the stator ring 10, so that the surfaces 24 on the stator ring 10 co-operate with the peripheral surface of the rotor and with the stator walls 11, 12 to form six liquid chambers 26 arranged annularly around the axis of the stator ring.

The rotor is provided with four radial ducts 27 arranged symmetrically around the axis of the rotor and extending between the peripheral surfaces of the rotor and the orifice 23, and the four ducts 27 communicate with the interior of the tubular end portion 21 of the shaft by four radial ducts 28 formed in the portion 20 of the shaft. Each peripheral portion of the rotor immediately ahead of the ducts 27, with respect to the direction of rotation of the rotor (indicated by the arrow A in Figure 2), is provided with a slot 29 extending transversely across the width of the rotor and arranged parallel to the radial plane of the associated duct 27, and four vanes 30 are slidably mounted one in each of the slots 29. The leading surface of each slot 29, with respect to the direction of rotation of the rotor, is provided with several radially extending grooves 31 (Figure 3) which form, with the opposing surface of the vane, ducts which communicate with a transverse duct 32 in the rotor. The four ducts 32 extend acrossthe width of the rotor and open into two annular channels 33 formed one on each'of' the opposing surfaces of the stator walls 11, 12 and each channel 33 communicates with a separate discharge port 34 via an annular duct 35 formed in the interior of the associated stator wall.

Each vane 30 comprises two parts consisting of two similar fiat metal blades 36 of a width equal to the width of the rotor. The blades are disposed face to face and formed into a sandwich by a layer 37 of rubber that is disposed between the two blades 36 and is bonded thereto. As made, and before the vane is placed in position in the pump, the two blades 36 are not in register (as illustrated in Figures 4 and 5), and when they are brought into register to enable the vane to be mounted in the pump the rubber layer 37 between the two blades is put in shear, and biases the blades in opposite directions, the direction of shear being such that a side edge of one blade is forced into sealing engagement with the stator wall 11 and a side edge of the other blade is forced into sealing engagement with the stator wall 12. The length of the vanes 30 is less than the depth of the slots 29, and springs 42 compressed between the inner ends of the blades and slots bias the blades radially outwards to bring the radially outer edges of the blades into sealing engagement with the internal peripheral surface of the stator ring 10.

.the liquid in the chambers down the grooves 31 and through the ducts 32 into the channels 33 in the stator walls 11, 12. The high pressure liquid in the channels 33 then flows into the annular ducts 35 and out through the two discharge ports 34. Since the high-pressure liquid in the grooves 31 discharges into the two channels 33 formed in the stator walls 11, 12 the liquid pressures acting on opposite sides of the rotor are equal, so that the rotor is hydraulically balanced. The grooves 31 extend the full length of the slots 29 and the high pressure liquid acts against the radially inner edges of the blades and forces the blades radially outwards, thereby reinforcing the action of the springs 42 and maintaining the radially outer edges of the blades in contact with the internal peripheral surface of the stator ring 10.

' The radial clearance between the peripheral surface of the rotor and the part-cylindrical surfaces 25 on the stator ring 10, and the axial clearance between the side walls of the rotor and the stator walls 11, 12 are kept as small as possible to prevent excessive leak-age of liq- -uid from the chambers 26 during passage of the vanes 30. The radial clearance is maintained constant due to the fact that the rotor is self-centering upon the elliptical portion, and the axial clearances are maintained constant due to the fact that the rotor is free to float axially on the portion 20 of the shaft and the liquid pressures acting on the opposite sides of the rotor are equal.

Any wear occurring on the side edges of the blades, or on the side surf-aces of the stator walls engaged by the blades, is taken up by relative movement of the two blades. Such relative movement, even after extensive us of the pump, is in practice quite small (e.g. not much more than about 0.01 inch) and the layer of rubber can be relatively thin, so that large shear forces can be applied and relatively large biasing forces will be available, even after wear of the vane or the surfaces of the stator Walls, to maintain the required sealing engagement between the blades and the stator walls.

Figures 6 and 7 show another construction of ,vane suitable for use in the pump of Figures 1 and 2 and comprising two blades 38 and 39 mounted in overlapping relationship, and formed into a sandwich by a layer of rubber 44 disposed between the two blades 38, 39

and bonded thereto. As in the vane of Figures 4 and 5. The blade 38 is positioned to the rear of the blade 39 with respect to the direction of rotation of the rotor, and the outer side portion of the blade 38, that is the side portion remote from the overlapping blade 39, is provided with a step 40 projecting forwardly in the direction of rotation of the rotor and lying in the plane of the front blade 39. The side surface 41 of the step 40 is spaced from the inner side edge of the blade 39 so that the side surface 41, the inner side edge of the blade 39 and the front surface of the blade 38 form a channel shaped duct 43 opening towards the high pressure side of the vane. The outer side edges of the overlapping blades 38, 39 are chamfered towards the rear, that is towards the low pressure side of the vane, and in operation the outwardly biasing forces acting on the blades due to the high pressure liquid in the duct 43 exceed the inwardly biasing forces due to the low pressure liquid acting on the outer chamfered side edges of the blades, so that the liquid pressure assists the action 'of the rubber layer 44 in urging the blades 38, 39 outwards in opposite directions, the outer side edge of the blade 38 into sealing engagement with the stator wall 11 and the outer side edge of the blade 39 into sealing engagement with the stator wall 12.

The vane of Figures 8 and 9 comprises three parts consisting of a rear fiat metal blade 45 having a width approximately equal to the width of the rotor, and two fiat metal blades 46, 47 having a width less than half that of the blade 45 and bonded one to each side of the front surface of the blade 45 by a layer of rubber 48. As made, and before the vane is placed in position in the pump, the outer side edges of the blades 46, 47 project outwards beyond the side edges of the blade 45, and when the vane is mounted in position in the pump the portions of the rubber layer 48 between each of the blades 46, 47 and the blade 45 are put in shear and force the outer side edge of the blade 46 against the stator wall 1 1 and the outer side edge of the blade 47 against the stator wall 12. During operation of the pump the high pressure liquid acts on the inner side edges of the blades 46, 47 and assists the action of the rubber layer 48.

In the single vane pump of Figure 10 the internal peripheral surface 50 of the stator ring 10' is contoured to provide a pump chamber having a constant diameter" across the axis of the stator ring, and the peripheral surface 50 co-operates with the circular peripheral surface of the rotor 19 to form an odd number of working or liquid chambers 26. A single 'vane 51 is slidably mounted in a slot 58 extending diametrically through the centre of the rotor and the shaft and transversely across the width of the rotor. The ends of the vane 51 engage diametrically opposed portions of the peripheral surface 50 of the stator ring, and upon rotation of the rotor the vane is reciprocated within the slot 58 and each of the two ends of the vane sweeps each liquid chamber in turn. Liquid at low pressure is fed to the liquid chambers through grooves 27 formed in the rear surfaces of the diametrically opposed portions of the slot 58, with respect to the direction of rotation A of the rotor, and high pressure liquid is forced by the vane down through grooves 31' formed in the front surfaces of the diametrically opposed portions of the slot 58 and into transverse ducts 32 as already described with reference to the pump of Figures 1 and 2. The stator walls of the single vane pump are similar to the walls 11, 12 of Figures 1 and 2 and have therefore not been illustrated in the drawings.

The ends of the single vane must provide adequate sealing engagement with the peripheral surface 50 of the stator ring, and the vane 51 comprises two similar blades 52 having head portions 53 arranged to engage the peripheral surface 50 of the stator ring, and tail portions 54 mounted in overlapping relationship and bonded together by a layer of rubber 56. The overall length of the vane, with the rubber layer 56 in an unstressed condition, exceeds the diameter of the pump chamber so that the rubber layer is put in shear when the vane is mounted in position in the pump and urges the blades outwards in opposite radial directions into sealing engagement with diametrically opposed portions of the peripheral surface 50 of the stator ring.

The head portion 53 of each blade is provided with a step 55 projecting forwardly in the direction of rotation of the rotor and lying in the plane of the tail portion of the other blade. The side surface of the step 55 on each blade is spaced from the opposing tail edge of the other blade to form two channel shaped ducts 57 on opposite ends of the composite vane and facing in the direction of rotation of the rotor. The radially outer edges of the head portions 53 are chamfered away fi'om the direction of rotation of the rotor, and in operation the outwardly biasing forces acting on the blades due to the high pressure liquid in the ducts 57 exceed the inwardly biasing forces due to the low pressure liquid acting on the chamfered outer edges on the head portions of the blades, so that the liquid pressure assists the action of the rubber layer 56 in urging the blades outwards in opposite radial directions into sealing engagement with the peripheral surface 50 of the stator ring.

Each layer of rubber or resilient material is shown in the drawings as comprising a single strip of material, the opposite surfaces of which are bonded to the two vane parts, but the layer may comprise a plurality of strips or pads lying in the same plane and each bonded to the adjacent opposing surfaces of the vane parts.

The pumps hereinbefore described will operate as motors if liquid under pressure is supplied to the-ports 34.

I claim:

1. A rotary device suitable for use as a pump or motor, said device comprising a hollow stator member and a rotor member rotatably mounted with small clearance between internal opposing side surfaces of the stator memben'said rotor and stator members having opposing peripheral surfaces one of which is circularand the other each vane being arranged to engage the inner peripheral surface of the stator and thereby sweep said chambers and displace liquid therefrom upon rotation of the rotor, wherein each vane comprises a sandwich of two vane parts and a layer of resilient material disposed between the two vane parts and bonded thereto, said layer of resilient material being in shear when the vane is mounted in position in the device, and urging the vane parts in opposite directions to provide sealing contact between a side edge of one vane part and one inner side surface of thestator and between a side edge of the other vane part and the other inner side surface of the stator.

3. A rotary device as claimed in claim 2, wherein the twovane parts are mounted in overlapping relationship with the projecting side edge of each vane part chamfered towards the low pressure side of the vane, and the projecting side edge of the vane part on the low pressure side of the vane is in the form of a step projecting towards the high pressure side of the vane, the side surface of said step cooperating with an inner side edge surface of the other vane part to form the sides of a duct opening towards the high pressure side of the vane, the pressure of liquid within the duct during operation of the device assisting the action of the layer of Y resilient material in urging the vane parts in opposite of which has a non-circular curvilinear profile in a plane Y perpendicular to the rotational axis of the rotor member, said peripheral surfaces cooperating with the internal side surfaces of the stator member to form an annular series of liquid chambers, said member with the circular peripheral surface having at least one slot opening through said circular peripheral surface and having high and low pressure conduits associated with each slot, and a vane slidably mounted in each slot, said high and low pressure conduits communicating with said chambers on opposite sides of each vane, and each vane being arranged to engage the non-circular peripheral surface and thereby sweep said chambers and displace liquid therefrom upon rotation of the rotor, wherein each vane comprises a sandwich of'two vane parts and a layer of resilient material disposed between the two vane parts and bonded thereto, the said layer of resilient material being in shear when the vane is mounted in position in the device and urging the vane parts in opposite directions to provide sealing contact between each vane part and at least one of said surfaces.

2. A rotary device suitable for use as a pump or motor, said device comprising a hollow stator and a rotor rotatably mounted with small clearance between internal opposing side surfaces of the stator, the outer peripheral surface of the rotor being circular and the opposing inner peripheral surface of the stator having a non-circular curvilinear profile in a plane perpendicular to the rotational axis of the rotor, said peripheral surfaces cooperating with the internal side surfaces of the stator to form an annular series of liquid chambers, the rotor having a plurality of slots opening through the circular peripheral surface and the side surfaces of the rotor directions.

- 4. A rotary device suitable for use as a pump or mo.- tor, said device comprising a hollow stator and a rotor rotatably mounted with small clearance between internal opposing side surfaces of the stator, the outer peripheral surface of the rotor being circular and the opposing inner peripheral surface of the stator having a noncircular curvilinear profile in a plane perpendicular to the rotational axis of the rotor, said peripheral surfaces cooperating with the internal side surface of the stator to form an annular series of liquid chambers, the rotor having a plurality of slots opening through the circular peripheral surface and the side surfaces of the rotor and having high and low pressure conduits associated with each slot, and a vane slidably mounted in each slot, said high and low pressure conduits communicating with said chambers on opposite sides of each vane and each vane being arranged to engage the inner peripheral surface of the stator and thereby sweep said chambers and displace liquid therefrom upon rotation of the rotor, wherein each vane comprises a sandwich including three vane parts bonded together by resilient material, the resilient material being in shear when the vane is mounted in position and yieldably urging a side edge of one vane part into sealing contact with one inner side surface of the stator and a side edge of another vane part into sealing contact with the other inner side surface of the stator.

5. A rotary device as claimed in claim 4 wherein each vane comprises said three vane parts and a single layer of said resilient material, one vane part being bonded to one surface of the layer of resilient material and the other two vane parts being bonded to the other surface of the layer of resilient material, the portions of the layer between the said one vane part and the said other two vane parts being in shear when the vane is mounted in position and yieldablyurging the said two other vane parts in said opposite directions and into sealing engagement with the opposing inner side surfaces of the stator.

of resilient material in urging the said other two vane parts insaid opposite directions.

7. A rotary device suitable for use as a pump or motor, said device comprising a hollow stator and a rotor rotatably mounted with small clearance between internal opposing side surfaces of the stator, the outer peripheral surface of the rotor being circular and the opposing inner peripheral surface of the stator having a non-circular curvilinear profile of constant diameter across the rotational axis of the rotor, said peripheral surfaces cooperating with the internal side surfaces of the stator to form an annular series of liquid chambers, the rotor having a slot extending diametrically through the centre of the rotor and transversely across the width of the rotor and having high and low pressure conduits communicating with said chambers, and a vane slidably mounted in the slot, each end of the vane being arranged to engage the inner peripheral surface of the stator and thereby sweep said chambers and displace liquid therefrom upon rotation of the rotor, wherein the vane comprises a sandwich of two vane parts and a layer of resilient material disposed between the two vane parts and bonded thereto, the said layer of resilient material being in shear when the vane is mounted in position and yieldably urging the two vane parts in opposite radial directions into sealing contact with the peripheral surface of the stator.

8. A rotary device suitable for use as a pump or motor, said device comprising a stator member, a rotor member rotatably mounted on the stator member, said members having opposing peripheral surfaces and side surfaces cooperating to provide a working chamber, and one of said members having a vane slot opening through the associated peripheral surface and having high and low pressure conduits associated with the slot, and a vane slidably mounted in the slot, said high and low pres 'sure conduits communicating with said chamber on opposite sides of the vane, and the vane being arranged to engage the said peripheral surfaces of the other member and thereby sweep the chamber upon rotation of the rotor member, wherein the vane comprises at least two vane parts and a layer of resilient material disposed between the two vane parts and bonded thereto, the said layer of resilient material being in shear when the vane is mounted in position in the device and urging the said two vane parts in opposite directions to provide sealing contact between each vane part and at least one of said surfaces.

9. A rotary device suitable for use as a pump or moto said device comprising a stator member having an internal peripheral surface and internal opposing side surfaces, a rotor member rotatably mounted with small clearance between said internal opposing side surfaces, said rotor member having a peripheral surface cooperating with the said surfaces of the statormember to provide a working chamber, one of said members having a vane slot opening through the associated peripheral surface and having high and low pressure conduits associated with the slot, and a vane slidably mounted in the slot, said high and low pressure conduits communicating with said chamber on opposite sides of the vane, and the vane being arranged to engage the peripheral surface of the other member and thereby sweep the chamber upon rotation of the rotor member, wherein the vane'comprises a plurality of vane parts and resilient material disposed between adjacent vane parts and bonded thereto, the said resilient material being in shear when the vane is mounted in position in the device and urging two of the vane parts in opposite directions to provide sealing contact between each of said two vane parts and at least one of said surfaces.

10. A rotary device suitable for use as a pump or motor, said device comprising a hollow stator member and a rotor member rotatably mounted with small clearance between internal opposing side surfaces of the stator member, said rotor and stator members having opposing peripheral surfaces one of which is circular and the other of which has a non-circular curvilinear profile in a plane perpendicular to the rotational axis of the rotor member, said peripheral surfaces cooperating with the internal side surfaces of the stator member to form an annular series of liquid chambers, said member with the circular peripheral surface having at least one slot opening through said circular peripheral surface and having high and low pressure conduits associated with each slot, and a vane slidably mounted in each slot, said high and low pressure conduits communicating with said chambers on opposite sides of each vane, and each vane being arranged to engage the non-circular peripheral surface and thereby sweep said chambers and displace liquid therefrom upon rotation of the rotor, wherein each vane comprises a plurality of vane parts and resilient material disposed between adjacent vane parts and bonded thereto, the said resilient material being in shear when the vane is mounted in position in the device and urging two of the vane parts in opposite directions to provide sealing contact between each of said two vane parts and at least one of said surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 705,835 Grove July 29, 1902 1,434,716 Marion Nov. 7, 1922 1,977,780 Stageberg Oct. 23, 1934 2,233,082 Kucher Feb. 25, 1941 2,521,595 Miller Sept. 5, 1950 2,619,040 Maisch Nov. 25, 1952 2,636,478 Smyser Apr. 28, 1953 2,662,483 Smith et al. Dec. 15, 1953 2,845,872 Farron et al. Aug. 5, 1958 2,855,857 Chien-Bor Sung Oct. 14, 1958 FOREIGN PATENTS 28,907 Great Britain of 1902 66,066 Denmark Dec. 1, 1947 754,347 Great Britain Aug. 8, 1956 

